19Sil

Buy a new ignition key switch lock cylinder with new keys to fix your issue and door lock cylinders if you don't want to carry 2 keys. A poorly cut key or worn out one will cause this problem. - https://www.ebay.com/itm/NEW-GMC-GM-OEM-IGNITION-KEY-SWITCH-LOCK-CYLINDER-2-DOOR-LOCK-CYLINDER-2-KEYS/351956362573

I drive my 1999 silverado every day with abs power connection unplugged underneath cab. Brake and ABS lights are turned on the dash, but brakes operate exactly like my 1990 k1500. When it is plugged in, the abs motor runs constantly.

12 Volt Microlamps - https://www.radioshack.com/products/radioshack-12v-microlamps-2-pack

I used EZ-Fit without a tube bender 2 months ago and it worked great!

My 1999 Silverado is 10ma

its a hall sensor mounted in the column that is activated by a magnet mounted on the cylinder that is pushed out by the key when it its inserted into the cylinder

its the ignition cylinder with key. had same prob

Thats what I did. Put a 3/4 ton in my '99. Mileage is higher by 40k but my state has no mileage statement on titles after 10 years.

99 silverado with 2000 2500 dash plunged right in and everything is perfect except mileage...Takes 30 minutes or more for trans temp needle to move. With cooler and fan my short box never heats up...

40 minutes

I had similar problems with my 99 Silverado. After extensive research it ended up being two things. The alternator and the instrument cluster. First I had the alternator tested and was told it was good. Then I replaced the instrument cluster with one from eBay. It helped some but was still slowly killing the battery, so I put a new alternator on and that finally fixed mine.